Artificial or assisted respiration of patients is necessary for various medical applications. Respirators are used for the artificial respiration of patients. The expiration gas expired by the patient can be used again at least partly as inspiration gas in some respirators, which are used especially in the area of anesthesia, i.e., these respirators are respiration systems with a breathing air circulation system.
Artificial respiration of patients is performed in the clinical area or even in case of respiration at home. For this, the breathing gas is to be fed to the patient through at least one breathing tube, especially the inspiration tube. The inspiration tube and an expiration tube are connected here, in general, to a Y-piece, and this is in turn connected to an elbow. The breathing gas is fed through the elbow to a respiration mask, which lies on the area of the face of the patient. The angular tube defines a breathing gas duct, through which the breathing air can be fed to the patient and the expired air can be removed. A breathing tube or the Y-piece can be connected to a tube port of the elbow and the respiration mask can be connected to a mask port of the elbow. The elbow has an anti-suffocation valve and carbon dioxide expiration openings. The anti-suffocation valve is used to prevent the patient from suffocating, especially in case of a defect of or damage to the respirator. The patient can thus draw breathing air directly from the environment of the elbow. Higher concentrations of carbon dioxide shall be prevented from building up in dead spaces of the elbow with the carbon dioxide expiration openings. It may be necessary for various applications of the elbow to have both the anti-suffocation valve and the carbon dioxide expiration openings opened or activated or to have only the anti-suffocation valve opened and to have the carbon dioxide expiration openings closed or deactivated. A complicated activation and deactivation by means of different switching members at the elbow is disadvantageously necessary for this.
An elbow with an anti-suffocation valve is known from U.S. Pat. No. 5,647,355. The anti-suffocation valve makes possible an automatic connection to the ambient air in case of a defect and has a primary inlet and a secondary inlet as well as an outlet.